1. Field of the Invention
The present invention refers to a device comprising a body defining a space containing or allowing the passage of a fluid, said body being associated to detecting means of at least a hydraulic or chemical-physical property of the fluid present in said space, the detecting means being operatively associated to a control system of the device.
2. Description of the Related Art
Some hydraulic devices, such as for instance some types of electric valves, integrate a flow meter designed to measure the flow rate of a fluid under control or to be treated by said device. Conversely, other hydraulic devices integrate detectors of one or more chemical-physical properties of a fluid, for instance some decalcifying devices for household appliances, which are associated to detecting means for water hardness. An application field exemplifying the problems underlying the present invention comprises mixing valves, and in particular those used for drink vending machines.
Some drinks, such as for instance non-alcoholic drinks, consist of a mixture of at least two liquid ingredients, usually a concentrated syrup and water, the latter suitably diluting the syrup. In some drink vending machines, the so-called post-mix type, syrup and water are mixed directly by the consumer, or by an operator, on the spot where the vending machine is installed. A post-mix vendor therefore comprises a device mixing the two components straight before they are supplied to the consumer. Said mixing device typically comprises at least two electric valves, for water and syrup respectively, installed so as to operate together and generally integrated into one module shaped as a mixing valve.
Some mixing valves used in the aforesaid field envisage the detection of hydraulic or chemical-physical properties of the water-syrup mixture. In particular, some applications envisage the use of flow meters for syrup and water, so as to measure the instantaneous flow rate of the fluid ingredients and to adjust the mixing ratio consequently by acting onto the mixing valve. In other applications the mixing operation is based on the measurement of the percentage of sugar, usually known as “Brix”, present in a final mixture comprising known ratios of water and syrup. In further systems, conversely, the mixing operation is regulated on the basis of the measurement of electric conductivity (see for instance U.S. Pat. No. 6,387,424) or refractive index (see for instance U.S. Pat. No. 6,374,845) referred to the mixture of water and syrup.
The integration into the mixing valve of means required to detect said quantities involves the presence of electric connections and contacts between said sensors and the control system supervising the operation of the valve. The presence of cables, beyond making the installation of the device quite complex and having given overall dimensions, limits the positioning of the detecting means within the valve. The electric contacts between the detecting means and the corresponding supply and/or signal cables then undergoes wear and tear in time, typically due to oxidation, considering that said devices often operate in moist environments; that is why high requirements of electric insulation are to be met. The presence of connections and contacts eventually involves the risk of unintentional dispersions of electric currents that can be dangerous, above all if we consider that said detecting means have to be put in contact with the liquid to be measured (for instance sensors of conductivity, refractive index, and so on). The presence of electric contacts further makes the separation and/or removal of components of the device quite difficult, for instance to washing and/or maintenance purposes.
The same applies also to the integration into a mixing valve as described before of a flow or flow rate sensor, aiming at enabling the measurement of the amount of one or more of the liquid ingredients used.